The Combustion and Mechanical Properties of Guanidine Phosphate-Boron Compound-Silica Sol Composite Flame Retardant on Wooden Structure Building Components

Abstract

ABSTRACT In order to develop a kind of wood with excellent flame retardancy properties, guanidine phosphate, boron compounds and silica sol were used as the main materials to formulate flame retardant solutions with different mass fractions, and to study the fire performance of wood structural building components after impregnation treatment with different flame retardant. The results showed that the LOI values of GPBS-4 and GPBS-5 increased by 82.22% and 97.78%, respectively, compared with that of the natural wood, and the residual charcoal rate of the wood was enhanced by 14.26% and 10.29% at 700°C, indicating that the composite flame retardants have high thermal stability. The results of cone calorimeter test showed that GPBS-4 had the most significant reduction of pHRR1, pHRR2 and THR, which were reduced by 43.01%, 41.06% and 36.97%, respectively, compared with the natural wood. The macroscopic morphology of the charcoal layer showed that the integrity of the charcoal layer of GPBS-4 was better, and the R-value of residual charcoal of GPBS-4 was reduced by 47.92% compared with that of the natural wood obtained by Raman spectroscopy, which indicated that the composite flame retardant effectively promoted the conversion of amorphous carbon into graphite structure, and facilitated charcoal formation in wood. In addition, the addition of silica sol in the flame retardant improved the effect on the mechanical properties of wood.